By the fifteenth century the Swiss method of warfare, in which disciplined foot soldiers fought in tightly formed units, was being imitated. The Germans and Spanish took notice when in 1479 Archduke Maximilian and his victorious Flemish infantrymen used their long pikes to prevent the mounted French knights from charging. The era of modern warmaking was at hand.

In this last volume of his classic history of the art of war, Hans Delbruck considers new developments: the use of gunpowder, the invention of firearms, and the employment of noisy large cannon that shot stone and, later, iron...